1. Field of the Disclosed Embodiments
The disclosure relates to resonant gas phase acousto-optic modulation.
2. Introduction
Optical phase modulators of various types are commercially available. However, they are not optimum for many uses including use in a self-diffraction densitometer incorporating an optical homodyne. Existing optical phase modulators generally use an electro-optic crystal. This presents optical surfaces through which an optical beam must pass. Because many potential uses for optical phase modulators may be in systems that ultimately need to detect optical beams of miniscule amplitude, it is important to minimize the number of optical surfaces through which beams to be modulated pass.
Electro-optic crystal optical phase modulators used currently also inevitably scatter some of the monochromatic laser light. Further, existing solid state optical phase modulators inevitably produce some, although small, residual amplitude modulation.
Thus, a need exists for an optical modulator that presents no optical surfaces through which a beam passes and therefore keeps spurious scattering to a minimum and may be used to improve, among other things, self-diffraction densitometers.